1. Field of the Invention The present invention relates to a range control system for expanding a range of an inputted voice and, in particular, to a system which can be used for a singing backup system in, for example, karaoke (recorded orchestral accompaniment) and also for a pronunciation backup system in, for example, chanting a Chinese poem or a sutra, or reading aloud a foreign language.
2. Description of the Prior Art
In karaoke, the singing backup system carries out, for example, real-time display (instructions) of lyrics of a song on a display unit, and melody line accompaniments. Thus, a person having some pitch sensitivity can sing a song to a degree that is acceptable for listeners, while watching displayed lyrics of the song and noticing at times a melody line rolling in the back.
However, even if one has some pitch sensitivity, if one""s voice compass or range is narrow (differences in vocal cords among individuals are large), it is often difficult to sing a song as expected even using the foregoing singing backup system. This problem is difficult to solve even if the music is transposed to match with a voice range of a singer using a transposing function, the voice range or the sound production band itself can not be expanded.
For solving the foregoing problem, a structure has been proposed in, for example, JP-A-4-294394, wherein a real-time pitch control is performed relative to an inputted voice for matching with pitches of model musical tones or model speech signal data so as to expand a voice range of a singer.
However, if such a pitch control is simply carried out, a tone color of the inputted voice is changed to be totally different from that of the singer.
Therefore, it is an object of the present invention to provide a range-control system which, even if a range of an inputted voice is expanded, does not deteriorate or spoil a tone color thereof.
It is another object of the present invention to provide a range control system, wherein even if a loudness of a voice outputted through the foregoing range expanding process differs from that of the inputted voice, it is adjusted to the level of the inputted voice loudness.
According to one aspect of the present invention, there is provided a range control system comprising an input section for inputting a voice: a fundamental frequency extracting section for extracting a fundamental frequency of the inputted voice; a pitch control section for performing a pitch control of the inputted voice so as to match the extracted fundamental frequency with a given frequency: a formant extracting section for extracting a formant of the inputted voice: and a formant filter section for performing a filter operation relative to the pitch-controlled voice so that the pitch-controlled voice has a characteristic of the extracted formant.
It may be arranged that the range control system further comprises a storage section storing a plurality of selectable pitch sequences as reference pitches; and a reading section for selecting one of the pitch sequences and sequentially reading the corresponding reference pitches, wherein the given frequency is a frequency of the corresponding reference pitch read out by the reading section.
It may be arranged that the storage section stores each of the pitch sequences corresponding to event changes, while storing acoustic effect data having periodic changes of pitches as parameters of time, depth and speed.
It may be arranged that the range control system further comprises an input loudness detecting section for detecting a first loudness of the inputted voice: and a loudness control section for controlling a second loudness of the voice subjected to the filter operation to match with the first loudness.
It may be arranged that the loudness control section controls the second loudness based on a ratio between the first loudness and a third loudness of the voice subjected to the filter operation, the third loudness detected by a loudness detecting section.
It may be arranged that the formant extracting section sequentially extracts formants of the inputted voice.
According to another aspect of the present invention, there is provided a range control system comprising an input section for inputting a voice; a fundamental frequency extracting section for extracting a fundamental of the inputted voice: a pitch control section for performing a pitch control of the inputted voice so as to match the extracted fundamental frequency with a given frequency; a formant extracting section for extracting a formant of the inputted voice: a formant filter section for performing a filter operation relative to the pitch-controlled voice so that the pitch-controlled voice has a characteristic of the extracted formant; an input loudness detecting section for detecting a first loudness of the inputted voice; and a loudness control section for controlling a second loudness of the voice subjected to the filter operation to match with the first loudness: a storage section storing a plurality of selectable pitch sequences as reference pitches; and a reading section for selecting one of the pitch sequences and sequentially reading the corresponding reference pitches, wherein the given frequency is a frequency of the corresponding reference pitch read out by the reading section.